Field of the Invention
The invention is in the field of processing of printed products and pertains to a device and a method for trimming of particularly multi-sheet folded printed products, such as newspapers, magazines and brochures.
Description of Related Art
Folded printed products are usually trimmed on the edge opposite the folded edge, as well as on both edges perpendicular to the aforementioned edges. This is termed front trimming or head-foot-trimming respectively.
The device described in EP-A 0753 386 has a plurality of pocket-shaped receiving compartments, which rotate around a common rotation axis and thereby are conveyed along a circular circuit. The receiving compartments are formed by two respective radially orientated supporting surfaces. The products are inserted into the receiving compartments with their folded edges ahead and come to rest against a support, which is in the region of the base of the compartment. The support is shaped and arranged such that the products are completely and deeply positioned in the compartment, i.e. the edge opposite the folded edge is completely within the compartment and clearly distanced from the radially outer, open side of the compartment. In this position, the products are orientated laterally, i.e. in the direction of the rotation axis or in parallel to the compartment base respectively and subsequently clamped with a clamping arrangement directly or indirectly against the supporting surface.
Subsequently, the head-foot-trimming is carried out first, and then the front trimming. For the corresponding trimmings, a respective trimming arrangement is provided, which at least comprises a stationary counter blade as well as blades, which are arranged in the compartments and are moved along with these. The counter blade for the head-foot-trimming is arranged in the movement direction of the compartments prior to the counter blade for the front trimming.
The blades, moved together with the compartments for the head-foot-trimming, are arranged on axially open sides of the receiving compartments, the moved blade for the front trimming is arranged on the open side of the compartments parallel to the compartment base. The stationary counter blades are in suitable positions, in which they may interact with the moved blade in the manner of scissors. As the supporting component or components trimming the front edges need to be led past the counter blade for the head-foot-trimming, the product must be located at different depths in the compartment for the front trimming and the head-foot-trimming. In the known device the product must, thus, already be inserted deeply into the pocket during the reception, in order to be able to carry out the head-foot-trimming.
Prior to the head-foot-trimming the products are fixed in the compartment by the clamping arrangement. After the head-foot-trimming the clamping arrangement is released and the product is laterally gripped by a dislocating arrangement. The dislocating arrangement moves the product along a supporting surface out of the compartment into the position for the front trimming. The clamping arrangement is then activated again and the product is again clamped in the shifted position. After the front trimming, the clamping arrangement is again released and the product is moved through the dislocating arrangement as far out of the compartment as necessary so that it can be taken over by an onward conveyor.
In the known device the products are fed by a gripper conveyor and dropped into the compartments or inserted into them deeply, respectively. Hereby they glide along a supporting surface freely, until their folded edge is stopped at the support. During this process it may occur that the products and/or product parts are dislocated in relation to one another. For the lateral (axial) orientation of the products, before their being clamped, a relatively large distance or period respectively is provided, which corresponds to a movement of the compartments along a circular course over an angle region of e.g. 60°. All the same, it may occur that during the subsequent clamping by the clamping installation the products are not completely orientated, which may lead to impure trimmed edges.
Moreover, the product is only brought into position for the front trimming after the head-foot-trimming and in this position clamped on its front edge by the clamping arrangement. Particularly due to the change between the clamping by the clamping arrangement and by the dislocation installation an arching upwards of the intermediate product region not held by the dislocation installation may have occurred, such that the front edge is not fixed evenly but with folds or dislocations. This may also lead to trimmed edges with reduced edge quality.
An object of the invention is to prevent the disadvantages of the state of the art and to provide a device for trimming of folded printed products as well as a corresponding method, in which the position of the products for achieving an optimum quality trimming is easily controllable.